Photovoltaic systems, also known as solar systems. Its development history page can be seen at a glance. After experiencing the component honeymoon period of 2006-2010, we had to reposition the industry. It is understandable to develop domestic demand, so the photovoltaic system has finally come to the forefront by the Chinese generously. However, for a variety of reasons, our system application basics are still in a relatively chaotic stage.
The ancients did not accumulate a lot of steps, and the details of the current decisions determine success or failure. These are all confirming the importance of the basic details. This article does not teach you to complain about policies, but suggests a down-to-earth improvement in the self-basic knowledge. Come take a look at these little details, how much do you know?

1. Photovoltaic cells are high-resistance current sources, and batteries are low-resistance voltage sources. This directly explains that we can short the components but never short the battery.
2. When the battery is covered, it will become an objective large resistance, and it will heat up quickly if it is not drained. This is also the fundamental principle of component and bypass diode activation switching.
3. 25 degrees Celsius under the STC state of the component is the operating temperature of the component and not the ambient temperature. So when you calculate the effect of temperature on the minimum operating voltage, you need to add an additional 25 degrees of panel temperature rise at room temperature. However, when calculating the effect of temperature on the maximum open circuit voltage, it is not possible to add 25 readings to the operating temperature. This 25 degree is a very considerable error for projects above 3 kW.
4. The same size of the same material (single crystal / polycrystalline) of the same power rating components, if the conversion efficiency is not the same, it is deceptive. This is also a law, no exception. The reason is very simple and will not be described.
5. The operating voltage of the component's maximum power point and the open circuit voltage of the component are a constant relationship of 0.8, which is very close. This relationship is very important and convenient in estimating the rationality of the inverter and system structure. At the same time, it also has great significance for the algorithm design of MPPT.
6. For the current components, the system is connected in parallel with more than 3 strings. There must be overcurrent fuse protection. A large number of system fires are caused by this error! This is determined by the maximum series fuse rating parameter.
7. The effect of floating dust or evenly distributed dust on system efficiency is not as terrible as it is supposed to be. It is basically within 5%, and in practice almost 2%.
8. Without the sun or drizzle of the sun, the output power of the system is very small. In fact, the open circuit voltage or working voltage of the component is still very high, even full load! Many installers of inverter replacements in Australia have suffered electric shocks. Keep in mind that on cloudy days, components may not output power, but it does not mean that it is dead. This is a common sense that is often overlooked.
9. East-Oriented Systems If the number of components is the same, they can be connected in parallel without serious voltage misalignment. Basically, as long as the light intensity is above 50 W/m^2, the component can work and output voltage. This explains the early start of the inverter, but the true output power is delayed for a while.
Simply list a few points, in fact, there are too many small details that are easy to be ignored. I hope that these are common sense that everyone has known and applied at all times, but if not, Xiaobian is very happy. You can understand from 9 articles. To the few that are ignored. The backwardness of the industry stems from the occlusion of knowledge. Xiaobian also sincerely hopes that everyone can discuss and contribute more.